What is an SQL-injection. How can it affect my site. How does it happen and how can I avoid it?
Since Firefox (2 and 3) and MSIE 7 started using Google’s (and others) system for blocking sites that produce harmful web pages the problem with SQL-injections have been put on the spot.
What happens is that an attacker hacks a site by placing their own SQL-code into the database of the victim system. Instead of just performing a DOS (denial of service) attack bringing the whole site down by for instance deleting all the tables or doing something else harmful to the site the attacker plants client side browser code in the database making all visitors run client side code that will infect their computer with a virus. This virus may do everything from listening in on traffic between the client (web browser) and bank applications, to connecting the client system to a botnet.
Needless to say, the SQL-injection attack has become a problem not so much for the owner of the originally defunct site as for the visitors to said site. (Although users of the web should not underestimate the consequence of a good virus protection, system update policy and secure browsing policy).
Since the owner of the vulnerable software won’t notice any detour from business as usual (and neither will most infected clients), nobody is the wiser to the problem.
This is why Google (and others) have started evaluating (and flagging) sites with bad content, and why Firefox and MSIE (and probably others) have started blocking them.
You may have thought GNU/Linux was written by idealistic Unix Gurus camped up with a bunch of Jolt-Colas in their mom’s basement, but a recent report from the Linux Foundation states the opposite. Since Linux kernel version 2.6.11 in Mars 2005 the number of developers has grown from 483 to 1,057 in version 2.6.24 (January 2008). However, the number of sponsoring companies has also grown from 71 to 186 in the same time.
The major contributors aren’t Mom’s Basement Inc. either. Companies like Novell, IBM, Intel, SGI, Oracle, Google and HP rank among the 20 largest contributors (counted in number of sponsored changes, and here sponsoring means paying employees to program those changes).
This is just the Linux kernel (some 8.5 – 9 million lines of code). However, the Linux kernel in itself is of little use to anyone. You have to add the GNU part of GNU/Linux, consisting of commands like fdisk, aspell, bison, ghostview, and wget to that, and you’ll be looking at a much larger number of lines of code. If we go even further adding programs from other projects (like the Mozilla project’s FireFox web browser, or the OpenOffice suite) more lines of code are added (for exact numbers see ohloh.net), and we’re still talking about programs supported by large companies (IBM, Sun, etc).
To sum it all up: no, GNU/Linux is not being written by enthusiasts in the basement anymore. It’s being written by large corporations for competitive reasons. Hardware manufacturers wants to make sure Linux will work on their hardware, software companies can be anything from Linux distribution owners (Red Hat, Novell, MontaVista), use embedded versions of Linux in their consumer hardware (Sony, Nokia, Samsung), or for other reasons (for instance Volkswagen uses Linux for in-car networking between different components).